Mahabali was banished because he became too popular on earth. The devas became resentful of him. In response to their plea, Lord Vishnu came down to earth as a small Brahmin boy, Vamana and, by trickery, exiled him. But not before Mahabali secured the privilege to visit his subjects one day in the year. Hence the popularity of this special day when the
spirit of Mahabali comes alive.